Light areas appearing larger and dark areas appearing smaller in Cycles
I'm probably going to get laughed into next week for this one.......but I think it's an optical illusion. Not only that but I think it also has to do with 3d world as opposed to 2d screen. A white A on a black background is always going to look bigger than a black A on a white background. Take the Olympic rings for example ......there is an actual formula for how thick each ring should be so that they all look the same thickness. The greatest example of this that I have ever seen is as you look up towards the alter in St. Peter's in the Vatican where Bernini makes the letters at the top of the columns larger than the ones at the bottom of each pillar as you look up the nave so that they all look the same hight from ground level. Anyway put a cube or a plane in the scene and measure it.